R22 (also known as HCFC-22) refrigerant is a powerful ozone-depleting substance and greenhouse gas that is currently being phased out worldwide under the Montreal Protocol.

The massive seizure is apprently the largest of its kind for Pakistan.

R22, still widely used in air conditioners and refrigerators, has a massive global warming potential (GWP) of 1,810.

The business responsible for the shipment was 'M/S Cool Corporation', which had originally imported it from China via Dubai, according to UNEP.

The company claimed to be importing R32 (also known as HFC-32). But one of the customs agents "noticed that the container was not classified for R32".

"The tank was pasted with large stickers declaring its contents as R-32 and flammable, which R22 is not," UNEP states.

Customs agents then "scanned the container and found the temperature and pressure readings on the tank also didn’t correspond to R32 refrigerant. Authorities then tested a sample, which confirmed the presence of R22".

Pakistani customs have now confiscated the tank and authorities are preparing to take further action if necessary.